Early characterization of the trifunctional enzyme complex from human liver. Described the enzyme as having hydratase, dehydrogenase, and thiolase activities, but did NOT determine which subunit carries which activity. The subunit-specific activities were later determined by PMID:8135828.

Review of the trifunctional enzyme. Provides protein sequence data and describes the enzyme activities.

KEY PAPER: Definitively assigned activities to specific subunits. Expression of alpha-subunit cDNA yielded hydratase and dehydrogenase activities. Expression of beta-subunit cDNA yielded ONLY thiolase activity.

Proteomics study of mitochondrial nucleoids. HADHB was found in native nucleoid preparations but did not cross-link to mtDNA, suggesting peripheral association.

Autophagy network study identifying HADHB-GABARAPL1 interaction.

HCMV-induced viperin interacts with TFP and reduces cellular ATP generation. Viperin relocalization affects TFP localization. Provides evidence for HADHB localization in mitochondria, outer membrane, and ER (during infection).

Interactome capture study identified HADHB among 860 RNA-binding proteins in HeLa cells. Many metabolic enzymes were unexpectedly found to bind RNA.

Large-scale interactome study showing HADHB-HADHA interaction.

4.2-A cryo-EM structure of TFP showing alpha2beta2 heterotetramer with V-shaped architecture. Demonstrates membrane association through concave surface.

3.6-A crystal structure of TFP. Confirms alpha2beta2 architecture. Shows substrate channeling pathway. Identifies active site residues for thiolase in beta subunit.

MTLN (mitoregulin) interacts with TFP to regulate beta-oxidation.

Interactome study confirming HADHB-HADHA interaction.

Mitochondrial proteome study confirming HADHB mitochondrial localization.

Large-scale multimodal cell mapping study that integrated AP-MS interaction data and immunofluorescence imaging for over 5,100 proteins in U2OS cells; HADHB is included among the proteins covered by this global subcellular architecture map.

Reactome reaction describing acylation of monolysocardiolipin (MLCL) to cardiolipin (CL) by HADH at the inner mitochondrial membrane. This activity is attributed to the HADH enzyme and likely represents an off-target or ambiguous annotation for HADHB, whose established function is long-chain 3-ketoacyl-CoA thiolase in beta-oxidation rather than cardiolipin remodeling.

Thiolase reaction in beta-oxidation pathway - appropriate for HADHB.

Hydratase reaction - this is actually HADHA's activity, but both subunits are annotated to the complex.

Dehydrogenase reaction - this is actually HADHA's activity.

Enoyl-CoA hydratase reaction (C16 substrate) in mitochondrial beta-oxidation. This is the hydratase activity of the TFP complex, which is carried by the HADHA alpha subunit; HADHB is annotated through complex membership rather than direct catalysis.

3-Hydroxyacyl-CoA dehydrogenase reaction (C16 substrate) in mitochondrial beta-oxidation. This dehydrogenase activity belongs to the HADHA alpha subunit of TFP; HADHB is annotated to this reaction only via complex membership.

Thiolase reaction - appropriate for HADHB.

3-Ketoacyl-CoA thiolase reaction on a C12 substrate (3-oxododecanoyl-CoA), yielding decanoyl-CoA and acetyl-CoA. This is HADHB's catalytic activity acting within its preferred long-chain (C10-C16) substrate range.

3-Ketoacyl-CoA thiolase reaction on a short-chain C6 substrate (3-oxohexanoyl-CoA). HADHB prefers long-chain substrates (C10-C16), so this short-chain thiolase annotation is likely an over-annotation; the activity is more typical of medium/short-chain thiolases such as ACAA2.

3-Ketoacyl-CoA thiolase reaction on a C8 substrate (3-oxooctanoyl-CoA). HADHB's preferred substrates are long-chain (C10-C16), so this medium-chain thiolase annotation is at the edge of or outside HADHB's physiological activity range and may represent an over-annotation.

3-Ketoacyl-CoA thiolase reaction on a C10 substrate (3-oxodecanoyl-CoA), yielding octanoyl-CoA and acetyl-CoA. This falls within HADHB's preferred long-chain (C10-C16) substrate range and is an appropriate annotation.